There is disclosed, for example in Patent Document 1, a technique wherein a back taper is imparted to a peripheral blade of an end mill or other rotary cutting tool having a plurality of helically shaped swarf discharge flutes formed on the periphery of the tool body from a leading end of the tool toward a trailing end, and a peripheral blade formed on an intersecting ridgeline of a rake surface of the swarf discharge flutes and a peripheral surface of the tool body (giving a shape in which an outside diameter of the peripheral blade leading from the leading end of the tool toward the trailing end gradually decreases). As a result, the area where the peripheral blade contacts the article to be machined is reduced, the cutting resistance decreases, tool breakage or other deleterious effects are prevented, and the operating life of the tool is prolonged.
[Patent Document 1] Japanese Laid-open Patent Publication No. 2004-209559